JPS5975544A - X-ray image tube and manufacture thereof - Google Patents

Abstract

PURPOSE:To obtain an image tube which is resistive to the atmospheric pressure and releases less amount of gas under the vacuum condition by exhausting an outer bulb sealed by a thin aluminum plate under the condition having no difference of pressure and then sticking a carbon fiber material to the outer surface of aluminum plate with the epoxy resin. CONSTITUTION:An input window 5 of the outer bulb 6 which is sealed at the aperture end of the cylindrical output part 4 having the bottom is made of a carbon fiber material 8 consisting of carbon having small atmoic number like a cloth of carbon fiber bonded to the outer surface of a very thin aluminum plate 7. An image tube 9 sealed by the thin aluminum plate 7 at the aperture end of output part 4 is set in a vacuum apparatus 10, and the insides of apparatus 10 and the bulb 9 are exhausted simultaneously to the vacuum condition in such a way as not generating pressure difference at the inside and outside of the aluminum plate. Thereafter, the carbon fiber material 8 made of a carbon fiber cloth is sticked to the outer surface of aluminum plate 7 within the apparatus 10; with the epoxy resin and is hardened. Thereby, the input window 5 can be formed.

Description

[Detailed description of the invention] [Technical field of invention] The present invention relates to an X-ray image tube and a manufacturing method thereof.

[Technical background of the invention]

Conventionally, as shown in Fig. 1, an X-ray image tube has a vacuum envelope consisting of a spherical input window 2 and a bottomed cylindrical output section 3, and the input window 2 is made of glass or aluminum. The input window 2 has an input diameter of 9 inches to allow the incident X-rays to pass through well and to maintain the atmospheric pressure. In the case of tM imager tubes, glass tubes with a thickness of about 4 mm are used, and aluminum tubes with a thickness of about 1 mm thick are used. It should be noted that a photocathode d5 is provided inside the envelope 1, a photocathode is provided on the input window 2 side, and an electron lens is provided on the output section 3 side (both lenses are not shown).

[Problems with background technology]

The functions of the input window 20 are roughly divided into two parts; one is to form the envelope 1 and maintain a high vacuum inside the X-ray image tube;
The other one is X#i! which is incident on the X-ray image tube! The aim is to transmit the light with as little attenuation and scattering as possible.

For the former, the envelope is required to be strong enough to withstand atmospheric pressure and to emit little gas in a vacuum. In order to ensure this strength, as mentioned above, glass requires a thickness of approximately 4 mm, and aluminum requires a thickness of approximately 1 mm. In addition, in order to maintain a high vacuum, high-temperature baking is required in the X-ray image tube manufacturing process to remove gases occluded and adsorbed in the envelope.
Aluminum or glass is used to control the structure.

Regarding the latter, in order to minimize attenuation and scattering of incident X-rays, it is preferable to use an element with a small atomic number and be as thin as possible. In the end, considering the balance between the former and the latter, the above-mentioned one has conventionally been used. In this way, the former requirement and the latter requirement are contradictory to each other, and as can be seen from the X-ray transmittance shown in Figure 2, the conventional model is extremely unsatisfactory with respect to the latter requirement. .

In FIG. 2, the solid line shows the case of J5 glass, and the broken line shows the case of aluminum.

[Uraaki's purpose]

An object of the present invention is to provide an X-ray image tube having an input window that improves the X-leg transmittance of the input window material to 1], withstands atmospheric pressure, and releases less gas in a vacuum, and a method for manufacturing the same. That's true.

[Summary of the invention]

In this case, the input window that constitutes the envelope is made by bonding carbon fiber material, which has a much stronger tensile strength than 9 aluminum, which is made of carbon with a small atomic number, to a thin aluminum plate. It is an X-ray image tube that has an input window with very good X-ray transmittance because it can be made very thin.

In addition, the present invention evacuates an envelope sealed with a very thin aluminum plate in a vacuum device with no pressure difference between the inside and outside of the aluminum plate, completes the formation of the photocathode, and then evacuates the envelope in the same vacuum. This is a method of manufacturing an X-ray image tube in which a carbon fiber material is bonded to the outer surface of an aluminum plate with epoxy resin within the device, cured, and then taken out of the vacuum device.

[Embodiments of the invention]

The X-ray image tube based on this i1 light is constructed as shown in FIG. 3, in which an input loyal member is sealed to the open end of a bottomed cylindrical output section 4 to form a vacuum envelope. . This human power loyal retainer consists of a very thin aluminum plate 7 with a thickness of 0.5 trvn and a carbon fiber material 8 made of carbon with a low atomic number, such as carbon fiber cloth, adhered to the outer surface of the aluminum plate 7. ing. Although not shown, an electron lens is housed in the output section 4 of the vacuum envelope, and a photocathode is provided on the input window A side.

Next, to explain the manufacturing method of the above-mentioned X-ray image tube, first, an X-ray image tube is produced in which a very thin aluminum plate 7 is sealed to the open end of the output section 4! is placed into a vacuum device 10 as shown in FIG. Then, in order to prevent a pressure difference between the inside and outside of the aluminum plate 7, the inside of the vacuum device 10 and the X-ray image tube! At the same time, evacuate the inside to create a vacuum.

Next, the X-ray image tube 2 is baked in a vacuum device at 200 to 300 degrees Celsius, which is much higher than the curing temperature of the epoxy resin, and the occluded and adsorbed gas inside the X-ray image tube is evacuated. Create a photocathode. Next, in the vacuum device 10,
A carbon fiber material 8, which is a carbon fiber cloth having a thickness of approximately 1 inch, is bonded to the outer surface of the aluminum plate 2 using epoxy resin.
If you harden it, you will have an input daughter.

Furthermore, carbon h1 is about 300/9/vm2, which is about 10 times the tensile strength of fibers compared to aluminum, so even if the aluminum plate 7 is thin, the composite material made by bonding the carbon fiber material 8 will be sufficiently stronger than aluminum. The Input Loyalty, a thin aluminum composite material, will be able to withstand atmospheric pressure.

〔Effect of the invention〕

According to the present invention, it is possible to provide an X-ray image saving method that converts an X-ray image into a sharp image with high sensitivity.

That is, since the aluminum plate 70 portion of the input tube is baked and evacuated in a vacuum, there is very little gas released into the tube after it is manufactured as an X-ray image tube, and the life of the X-ray image tube is long. Furthermore, in this invention, since the carbon fiber material 8 is laminated to the aluminum plate 7, an X-ray image tube can be obtained which can withstand atmospheric pressure and has a very good input faithfulness of X-ray transmittance. This X
Medical X-ray equipment that uses a radiation image tube can greatly reduce the X-ray exposure of patients, has excellent sensitivity, and greatly improves image contrast, improving diagnostic performance and is extremely useful. be.

It is particularly effective for viewing X-ray fluoroscopic images with low energy radiation quality.

Next, FIGS. 5 to 7 show various modifications of the present invention, which provide the same effects as the above embodiments.

First, in the modified example shown in FIG. 5, the vacuum sealing and pressure resistance functions are performed separately, so that the thick aluminum material is too small for the input section that maintains the vacuum sealing shown in FIG. In this modification, the input fluorescent surface holding aluminum substrate conventionally placed in the X-ray image tube is usually about 0.5 scale thick, so this aluminum substrate is
) is used in conjunction with the vacuum seal plate 11). Therefore, in this modification, an input fluorescent surface is formed on the inside of the tube of the vacuum seal plate 11. A heat-resistant and pressure-resistant cover 13 is attached to this X-ray image tube 12- as shown in FIG. With this heat-resistant and pressure-resistant cover 13 attached, gas removal and photocathode formation of the X-ray image tube are performed. That is, the air in both the inside of the X-ray image tube 12 and the space between the heat-resistant rigid pressure cage 13 and the vacuum airtight plate 11 is exhausted at the same time.
Make sure that there is no pressure difference between the front and back of the vacuum-tight plate 1.
While preventing its deformation, the X-ray image tube and tube are evacuated and heated to remove gas, and then a photocathode is created.

Next, the heat-resistant and pressure-resistant cover 13 is placed in a vacuum chamber with the cover 13 still attached, and the heat-suppressing surface/pressure cover 13 is removed inside the vacuum chamber, and the heat-resistant surface 13 is removed to ensure good X-ray transmittance as shown in the same figure (C). Install the pressure-resistant cover (input window) 24. This pressure resistant cover LA
In order to improve the X-ray transmittance, carbon fibers, which have a tensile strength about 10 times that of aluminum, are attached to both sides of a thin aluminum plate 15 using epoxy resin, as shown in Figure (d). ing. In contrast to the conventional aluminum input window of about 2 m, the aluminum plate 15 is made of 0.51 m of aluminum material, and the membranes 16 and 17 made of carbon fiber and pasted with i5 xy resin each have a thickness of 0.5 tta. did. Since the X-ray absorption of carbon fiber is much lower than that of aluminum, the X-ray transmittance is almost determined by the thickness of the aluminum plate 15. Therefore, this modified example also greatly improves the X-ray transmittance, and the effect is particularly remarkable in areas where the quality of X13 radiation is low. Also, instead of using the side heating pressure-resistant cover 13, the inside of the vacuum device and the inside of the X-ray image tube 12 are simultaneously evacuated to remove gas so that no pressure difference occurs between the inside and outside of the XH image tube 12 inside the vacuum device.・At the same time as making the photocathode, it is also possible to attach the pressure-resistant cover LA inside the vacuum device. or,
The input fluorescent surface is not formed directly on the vacuum seal plate 11 as in this modification, but can be placed inside the tube as in the conventional case. In this case, the vacuum seal plate 1 does not need to be convex. do not have.

In addition, the input window, that is, the air pressure resistance z<-14 and the vacuum seal plate 11
Since the space formed by this is vacuum-separated from the space containing the electron lens, it does not require an island vacuum like the space containing the electron lens. Since it is sufficient that no significant pressure difference occurs, the pressure-resistant cover L1 does not require advanced gas removal such as heating gas removal.

Next, in the case of X-ray image positive LL in FIG. 6, no input fluorescent surface is formed on the vacuum airtight plate 19, and the input fluorescent surface is disposed inside the tube. Therefore, there is no need for the vacuum airtight plate 19 to have a convex structure, which is necessary as an input fluorescent surface.
Can be made very thin. In this variant, it is an aluminum plate with a thickness of 100 μm. Attach heat resistance and air pressure resistance/4-20 to this x% image 91B as shown in the same figure (b),
After removing the gas from the line image tube and forming the photocathode, we removed the heat-resistant and pressure-resistant cutter-20 in a vacuum room.
C) Resistance pressure like/? -, install 21. This pressure-resistant cover shell does not need to be convex as shown in the figure, so the pressure-resistant cover shell does not need to have a tonality. If it has tensile strength, it can withstand atmospheric pressure in a concave state.

Therefore, only the film 23 made of carbon fibers attached to the aluminum plate 22 and formed into a sheet using epoxy resin or the like can withstand the damage. Note that carbon fiber membranes cannot always completely eliminate pinholes like metal membranes, so a malleable film such as a resin film + Jincho thin film is used to maintain vacuum tightness, as shown in the same figure (C). They may be hung together or pasted together.

Next, the X-ray image tube 24 shown in FIG. 7 includes a space containing an electron lens separated by a thin gold striped film, for example, an aluminum film 25 with a thickness of 100 μm, and a space containing carbon fibers surrounded by epoxy resin. It consists of an input window 26 made of a film and a space formed by the aluminum film 25. The input window 26 has no heat resistance, and the resin used therein deteriorates when the temperature reaches about 150°C. Therefore, this X-ray image tube 24
In the gas removal and photocathode formation process, the partition wall of the space containing the frost and the child lens is sufficiently heated to the temperature required for gas removal and photocathode formation, and the input window 26 is opened from the outside of the envelope.
In order to prevent the resin used in the process from deteriorating, cool it down using a vacuum cleaner or the like. In addition, the aluminum film 26 is placed in a vacuum both times.
Since the part of the partition wall containing the electron lens is heated, it is necessary to heat it using high frequency heating. In this way, the manual window 26 is assembled before the gas is removed from the X-ray image tube LA and the photocathode is formed.

Incidentally, also in FIGS. 5 to 7, similar to the above embodiment,
The electronic lens and photoelectric 1st surface are omitted.

[Brief explanation of drawings]

Figure 1 is a cross-sectional view of a conventional X-ray image tube. Figure 2 is a characteristic curve diagram showing the relationship between X-ray transmittance and X-ray energy in a conventional envelope. Figure 3 is a cross-sectional view showing an X-ray image tube according to an embodiment of the present invention, FIG. 4 is a cross-sectional view showing a method for manufacturing an X-ray image tube according to the present invention, and FIGS. One by one shows three examples of modifications. 4...Output 'iB% mutually...input window, mutually...vacuum envelope, 7...aluminum plate, 8...carbon fiber material, 9...X-ray image tube, 10... ...Vacuum equipment. Applicant's representative Patent attorney Takehiko Suzue Figure 1 Figure 2

Claims (3)

[Claims] (1) An X-ray image tube in which the envelope includes a bottomed cylindrical output section that accommodates an electron lens, and an input window sealed to the open end of the output section, the input window comprising: An X-ray image tube comprising a thin aluminum plate and a carbon fiber material bonded to the aluminum plate. (2) The X-ray image tube according to claim 1, wherein the vacuum section is separated into two parts: a part including the electron lens and a part facing the input window. (3) In a vacuum device, an envelope with a very thin aluminum plate sealed to the open end of the bottomed cylindrical output part is evacuated with no pressure difference between the inside and outside of the aluminum plate, and the photocathode is formed. A method for manufacturing an X-ray image tube, characterized in that the carbon fiber material is bonded to the aluminum plate with epoxy resin in the same vacuum apparatus, cured, and taken out of the vacuum apparatus.